Combustion chamber



Oct. 4, c M|LLER 1,881,325

COMBUSTION CHAMBER Filed Jan. 28, 1931 INVENTOR Patented @et'. 4, 1932 star CARROLL MILLER, OF

PITTSBURGH, PENNSYLVANIA, ASSIGNOB, TO THERMATOMIC CARBON COMPANY; OE PITTSBURGH, PENNSYLVANIA, A CORPORATION OF DELA- WARE COMBTTSTION CHAMBER Application filed January 28, 1931. Serial No. 511,709.

ture of carbon black in which the hydrocarbon gas being decomposed is diluted with the gaseous products of combustion furnished by a burning fuel, the dilution being accomplished before the hot combustion gases have dropped in temperature a 1 substantial amount. Y

The present invention is an improvement over the process and apparatus developed by Ellwood B. Spear and described inthe Spear applications, Ser. No. 221,245, filed September 22, 1927, Ser. No. 300,133, filed August .16, 1928, and Ser. No. 384,650, filed August 9, 1929.

According to the preferred procedure in the Spear process, the hot combustion gases from a burning fuel, while still retaining their sensible hes. are mixed with a hydrocarbon gas to be oecomposed. The inixturecf the hot diluent gas and the hydrocarbon gas is passed over extensive hot contact surfaces to decompose the hydrocarbon gas and yield solid carbon particles. Part of the carbon thus formed is deposited upon'the hot contact surfaces and part is entrained in and swept along with the gas, which is then passed through devices for quickly cooling it and separating the carbon from the gas.

When a hydrocarbon gas, such as methane or natural gas, is heated, the hydrocarbon breaks down, yielding solid carbon particles and hydrogen. This reaction is endothermic. The temperature at which this reaction takes place, as well as the speed of the reaction, is profoundly afiected by the presence of hot contact surfaces. It hot contact surfaces are present, the decomposition takes place at a lower temperature and much more rapidly than would be the case if the gas were heated in a container which did not contain extensive contact surfaces.

In the apparatus disclosed in the applications of Spear, Serial Numbers 300,133 and 384,650, the decomposition of the hydrocarbon is caused to take place in a retort containing checkerwork which is highly heated and through which the gas is passed to decompose the hydrocarbon. The retort is divided by a firebrick wall into two chambers which are duplicates of each other. A

tree passage between the chambers is provided by an opening over the top of the partitionwall. Each chamber contains refractory checkerworl: forming two checkerwork reaction zones, spaces or free chambers being left at the tops of the chambers so that mixing may be accomplished in these .free chambers.

Fuel gas and air may be introduced into the bottom of either or both chambers to apply a heating blast to the checkerwork in either or both chambers.

As stated in the Spear application, Ser. No.

384,650, filed August 9, 1929, the preferred operation of the apparatus is as follows The checkerwork in both chambers is imtially'heated, the gases of combustion passing .7

upwardly through the chambers and escaping through a'oap valve in the top of the retort.

tter a cold retort has been heated up, it is in condition to perform its regular reversing cycle for the production or" carbon black.

This reversing cycle will now be described. A. heating blast is supplied to the bottom of one or the other of the chambers of the retort,

the air and fuel gas burning in the chamber and passing up though the checkerwork. The highly heated gasesof combustion, which serve as the diluent'gas during the decomposition of the hydrocarbon or run gas, pass over the top or" the partition into the other chamber. The run gas, which is usually natural gas, is admitted tirough a pipe into the top of the retort, and mixes with the stream of diluent gas in the above mentioned mixing space. This mixture of diluent gas and run gas passes down through the checkerwork in the other chamber which has already been highly heated by the blast as above described. I

The run gas is decomposed into solid carbon particles and hydrogen. lhe hydrogen is swept along with the stream of gases and out of theretort. The recoverable carbon is entrained in the gas stream and is recovered in suitable filtration apparatus. 7 7

During this part of the cycle, the checkerfmate relation with work in the second chamber tends to fall in temperature, and tends to become less eflicient as a decomposing zone. l/Vhen this has progressed to such a degree as to substantially decrease the efliciency of the apparatus, the flow of gases through the two chambers is reversed, the fuel gas and air being admitted to the bottom of the second chamber where it burns, passing up through the checkerworkin the new direction of How. The run gas is admitted, as in the first part of the cycle, into the top of the retort, and mixes with the stream of diluent gas in the space above the checkerwork. This mixture of diluent gas and run gas passes down through the checkerwork in the chamber which, in the first portion of the cycle, was the first chamber. Thisfmixture of diluent gas and run gas comes into intithe checxerwork so that the run gas is decomposed into solid carbon particles and hydrogen. The carbon particles are swept along by the stream of gas through the discharge pipe into the apparatus for cooling and filtering out the carbon particles.

' In commercial operation, temperature of the checlterwork in both chambers usually has dropped sufficiently at the end of two half cycles so that they will. no longer operate efficiently to decompose the mixture of run gas and diluent gas. The temperatures of the cheekerwork in the two chambers is thereupon boosted by applying a heating blast through the burners at the bottoms of the two chambers.

After the temperatures in the checkerwork of the two chambers have been thus boosted, the carbon production is then continued, first using the checkerwork in one chamber as the reaction Zone, reversing and then using the other checkerwork as the retakes place in a chamber containing refractory checkerwork; and it has been found that as the operation of the retort continues, the

checkerwork at the top tends to fall in temperature, so that the gaseous products of combustion, when they reach the mixing space, are not at the maximum temperature reached thereby. The mixing of the combustion gases at the maximum temperature reached thereby with the run gas 1s desirable in order [to most efficiently operate the retort.

My apparatus, as hereinafter more fully described, resembles the Spear apparatus in that both apparatus are arranged to decompose the hydrocarbon gas by passing it, to-

gether with the preheated diluent gas, over extensive hot contact surfaces. My apparatus is in the nature of an improvement upon the apparatus disclosed in the Spear applications, in that the mixing of the diluent gas with the hydrocarbon gas takes Silocel.

place at the maximum temperature reached by the products of combustion which constitute or form a part of the diluent gases. In accordance with my invention, the combustion gases are preferably formed in, a combustion chamber which is so connected with the mixing chamber of the retort in which decomposition of the hydrocarbon gas takes place thatthe gaseous products of combustion are delivered to the mixing chamber at substantially the maximum temperature reached thereby. I thus increase the ethciency of operation of the apparatus, obtaining a larger yield from the same volume of hydrocarbon gas. Furthermore, there is less tendency for the checkerwork in the decomposition chamber to drop quickly in tempera ture so that the same has to be blasted to againheat up this checkerwork to the temperature proper for eficient decomposition of the hydrocarbon gas.

I will now describe in detail my improved apparatus. In the drawing the figure shows more or less diagrammatic and principally in central vertical section a preferred embodiment of my'improved apparatus.

The preferred apparatus as shown'is of the general type shown in the Brownlee & Uhlinger Patent No. 1,520,115. Generally speaking, it consists of a retort containing checkerwork which is highly heated and through which the gas is passed to decompose the hydrocarbon.

Referring to the illustrated embodiment of the apparatus, decomposition of the hydrocarbon gas takes place in a retort 1. The efiiuent gas which issues from the retort and which contains the entrained carbon particles passes to a chamber 2 in which a water spray 3 is discharged to cool the gas. The hot gas converts the water into steam, the latent heat of evaporation serving efficiently to cool the gas. The gas then passes downwardly through a conduit a into the lower portion of the chamber 5 where the gas passes through thefabric bags 6 which are shaken from time to time to dislodge the carbon. Thecarbon from the chamber 5 accumulates in a bin 7 from which the same may be discharged under control of a valve 8. The general layout above described, and particularly the means for cooling and collecting the carbon black, is similar to that described in the Browulee Uhlinger Patent No. 1,520,115. The temperature of the cooling chamber 2 is preferably automatically thermostatically controlled, as described in the Brownlee Uhlinger patent.

The retort 1 has a steel plate casing 9 and a lining-consisting of a facing 10 of firebrick and a backing 11 of refractory'insulation material, such as asbestos or theporous insulating material sold under the trade-mark Checkerwork 12 is supported'in the retort 1 by supporting columns or upright Lee-1,325

bricks 13, forming relatively open spaces or chambers 14 beneath the checlrerworlr. Above the che'ckerwork is a mixing chamber 15. i

An inlet pipe 16 discharges into the chamber 14% to supply a mixture of fuel gas and air. In this way a heating blast can be discharged into the chamber 14. The top or dome of the retort is provided with an opening or 17 which is normally closed by a cap valve 18. A pipe 20 discharges into the top of the retort for introducing the hydrocarbon to be decomposed, which is commonly known as the run gas in this industry.

The bottom of the retort 1, that is to say the open space 14 beneath the checkerwora, is connected to the spray-tower 2 by a discharge pipe 21 provided with ashut-ofi' valve 22. A smaller retort 23 is connected to the passage 17 to supply the diluent gases which are to be mixed with the run gas. The retort 23 has a steel plate casing 24 and a lining consisting of a facing 25 and a backing 26, similarly as in the case of the retort 1. l i ithin the retort 23 is a suitable mass of checker l: 27. Air is blown or otherwise introducec the retort 23 through a pipe controlled by valve 29. Fuel gas is supplie through a valve-controlled pipe 30 to 1111 incoming air and burn in the ret refractory conduit, consisting of a facing 31 and a backing 32 of refractory insulation materiahconnects the retort 23 to the opening or passage 17. The operation of the apparatus is as follows:

The checkerwork 12 is initially heated by a heating blast through the blast inlet 16. During this preliminary heating, which occurs when a cold retort is to be brought into operation, the gases of combustion pass up through the checkerwork 12 to initially heat them. The combustion gases are allowed to escape through the opened cap valve 18 in the top of the retort.

After a cold retort has been heated up it is in condition to operate for the production of carbon black. To do this the retort 23 is operated to supply hot gaseous products of combustion to the opening 17. The proportion of air admitted through the pipe 28 and the fuel gas admitted through the supply pipe 30 may be adjusted by manipulation of the valves in these pipes so that the products of combustion as they emerge from retort 23 are principally or all carbon dioxide, or principally carbon monoxide, or a mixture of carbon dioxide and carbon monoxide, together, of course, with the nitrogen derived from the air and water vapor from the oxidation of the hydrogen constituent of the hydrocarbon gas. The effect of the different proportions of the carbon dioxide and carbon monoxide is discussed in detail in the Spear application, Serial No. 384,650.

The highly passage heated gases of combustion,

which serve as the diluent gas during the decomposition of the hydrocarbon or run gas pass from the opening or passage 17 into the mixing chamber 15. The run gas, which is usually natural gas, is admitted through the pipe 20 into the top of the retort andmixes with the stream of gaseous decomposition products from the retort 23. This mixture of diluent gas and run gas passes down through the checkerworlr 12, which ias been highly heated by the blast previously applied to it; The volume of run gas admitted may be controlled by a valve. V

The run gas is decomposed into solid carbon particles and hydrogen. The hydrogen isswept along with the stream of gases out of the retort 1. The recoverable carbon is entrained in the gas stream and is recovered in the filtration apparatus.

The decomposition of the -run gas into hydrogen and carbon particles 1S apparently a surface phenomenon. The decomposition apparently takes place, or takes place initial- I 1y, at the highly heated surfaces of the refractory checlrerworlr 12, and the carbon particles so formed are partly lodged upon the checkerwor and are partly swept along and entrained in the stream of gas. In order to secure an adequate yield of carbon, the zone in which the hydrocarbon gas is decomposed should contain extensive hot contact surfaces. In the form of retorts illustrated, such surfaces are provided by the checkerworlz'.

I use the word checkerworlr as a term of general description and not of limitation, and intend to include under such term materials of any shape, whether in the form of regular bricl: or not, so placed in the retort chamber as to exposed extended surfaces with passages between them to permit the flow of the gas. I use the word checlzerwork to dis tinguish such a construction on the one hand from an open chamber in which the'only surface presented is that of the chamber walls which is so small that but little decomposition of the run gas would result, and on the other hand. from beds of granular material in which the pieces of material and the passages between them are so small that the carbon would be practically all caught in the bed ofmaterial and could not be recovered.

Due to the fact that the reaction is endothermic, the temperature of the mixture ofdiluent gases and run gas tends toafall, and therefore there is a tendency for I the checkerwork 12 to fall in temperature below that at which most efficient operation of the retort may be carried on. Accordingly, it

may be found advantageous to discontinue theo'peration of the retorts 1 and 23 in the manner just indicated, and to blast the checkcase the cap valve 18 is opened and a mixture of fuel gas and air is admitted through the conduit 16 to pass upwardly through the checkerwork 12 and highly heat the same. When the checkerwork 12 has thus been brought to the proper temperature, the introduction of combustible mixture through the conduit 16 is discontinued, the cap valve 18 is closed and the normal flow of diluent gas and run gas doWnwardlyth-rough the checkerwork 12 is maintained until such operation of the apparatus must be again interrupted. g

It will be apparent that my improved apparatus has the advantage over previously known apparatus that there is no substantial loss of heat from the gaseous products of combustion prior to the time they are mixed with the run gas for decomposition of the run gas in contact withvthe checkerwork 12. Due to the arrangement of my improved apparatus, a great deal more heat per unit of products of combustion is supplied to the incoming run gas than has been previously possible. As this arrangement permits the introduction of more natural gas to be cracked, with the consequent relatively larger volume of products of decomposition, the total flow of gas through the retort 1 is much increased; and therefore the velocity is proportionately greater, resulting in a larger yield per retort and more efiicient operation of each retort 1. Due to this improvement a greater yield of carbon per thousand feet of gas may be obtained, due to less carbon being consumed by the various reactions. 7

While I have illustrated and described one specific form of apparatus for the manufacture of carbon black, it will be understood that the invention is not restricted to the particular construction and arrangement shown, but may be variously modified Within the contemplation of the invention and under the scope of the following claims:

I claim:

1. Apparatus for the production of carbon black comprising a chamber containing checkerwork adapted to be heated, means for burning a fuel, means for mixing a hydrocarbon gas with the hot combustion gases produced thereby at substantially the maximum temperature reached by said combustion gases and passing the mixture over the heated checkerwork, thereby decomposing the hydrocarbon gas to yield solid carbon particles, and means for separating the carbon particles from the gaseous decomposition prod ucts.

2. Apparatus for the production of carbon black comprising a chambercontaining extensive heat exchanging surfaces, means for applying a heating blast to heat said extensive heat exchanging surfaces, means for burning a fuel, means for mixing a hydrocarbon gas with the hot combustion gases produced therebyat substantially themaximum temperature reached by said combustion gases and passing the mixture over the extensive heat exchanging surfaces, thereby decomposing the hydrocarbon gas to yield solid carbon particles, and means for separating the carbon particles from the gaseous decomposition products.

3. Apparatus for the production of carbon 1 black, comprising a retort providing a reaction chamber and a mixing chamber, means in the reaction chamber affording extensive heat exchanging surfaces, means for burning a fuel and passing the combustion gases produced thereby to said mixing chamber at substantially the maximum temperature reached by said combustion gases, means for mixingwith said combustion gases a hydrocarbon gas to .be decomposed, the mixture passing over the exensive heat exchanging surfaces to thereby decompose the hydrocarbon gas and yield solid carbon particles, and means for separating the carbon particles from the gaseous decomposition products.

4:. Apparatus for the production of carbon black, comprising a retort providing a reaction chamber and a mixing chamber, means in the reaction chamber affording extensive heat exchanging surfaces, means 7 for applying a heating blast to heat said extensive heat exchanging surfaces, means for burning a fuel and passing the combustion gases produced thereby to said mixing chamber at substantially the maximum temperature reached by said combustion gases, means for mixing with said combustion gases a hydrocarbon gas to be decomposed, the mixture passing over the extensive heat exchanging surfaces to thereby decompose the hydrocarbon gas and yield solid carbon particles, and means for separating the carbon particles from the gaseous decompositionproducts.

In testimony whereof I have hereunto set my hand. I

CARROLL MILLER. 

